1. Field of the Invention
The present invention relates to a flat antenna, and more particularly to a flat antenna having a meandering configuration constructed by such a way that conductive traces are printed on multiple layers of dielectric substrates and electrically connected by plated through hole (PTH) process. The flat antenna is suitable for use in any wireless equipment such as a wireless mobile phone, a wireless modem or for use in a local area network (LAN).
2. Description of Related Art
The rapid developments in the wireless communication field have led to a variety of new communication apparatuses and technologies in recent years. Basically, these communication products are required to be multi-functioning in a miniature size. Such requirements are also applied to wireless antennae used with the new communication products. The requirements are able to be achieved by the antenna structure consisting of a substrate (70) on which meandering radiator (71) is formed, shown in FIG. 1. With such a configuration, the length and the area of the antenna can be effectively increased within a limited substrate.
Besides the aforementioned mini size requirement, a wireless antenna needs to have multiple channels and be able to support wide operation frequency bandwidth. For example, some established operation frequency standards include EGSM (880–960 MHz), DCS(1710–1880 MHz), PCS(1850–1990 MHz) and WCDMA/CDMA2000(1920–2170 MHz). These standards are mainly separated into two groups based on an operation frequency band, i.e. a first operation frequency band (880–960 MHz) with 80 MHz bandwidth and a second operation frequency band (1710–2170 MHz) with 460 MHz bandwidth.
However, the actual frequency bandwidth in the second frequency band (1710–2170 MHz) used by a conventional antenna is only 280 MHz (1710–1990 MHz). Obviously, a conventional antenna does not effectively utilize such a wide operation frequency bandwidth.
Further, the antennae of the wireless communication products can be distinguished into an external type and an internal type based on the installation position. The most commonly used external type antenna has a circular appearance if the antenna is created as a spiral configuration. To vary the appearance of the antenna, the flat structure is suitable for forming a rectangular, square or an elliptical antenna.
Moreover, the chip type antenna also can be implemented by the flat structure, which could be electrically mounted on a desired circuit board through the surface mounting technology (SMT) thus reducing the cost of the packaging and connecting processes so that the flat structure is quite suitable for use as an internal type antenna.